1. Field of the Invention
The present invention relates to an X-ray mirror apparatus for use, for example, in an X-ray microscope and a method of manufacturing the same.
2. Description of the Related Art
An X-ray has a shorter wavelength than that of visible light and a greater transmission power than an electron beam. Since the X-ray has an absorption wavelength band inherent to each element, it is possible to identify a specified element through the utilization of the aforementioned nature of the X-ray as well as a fluorescent X-ray. For this reason, the X-ray provides an important means capable of obtaining atomic level information relating to an object.
In the X-ray wavelength region, however, the refractive index of an object is very approximate to unity. It has, therefore, been difficult to manufacture lenses and mirrors for X-rays, which have the same functions as that of a refractive lens and a direct incident type reflecting mirror used in the visible region.
A recently developing X-ray microscope uses an X-ray mirror utilizing such a nature that when an X-ray is incident at a very great angle on a reflection surface, that is, when it is incident at a grazing angle thereon, a total reflection occurs. Known as an X-ray mirror is a mirror having a Wolter-type reflecting surface. This mirror has a substantially cylindrical configuration, and its inner surface constitutes a reflection surface of a hyperboloid of revolution and a reflection surface of an ellipsoid of revolution in a continuous relation. These reflection surfaces has a common focal point F1. With a focal point F2 as an object point the mirror reflects an X-ray, which passes through the object point, on the aforementioned two reflection surfaces, forming an image on a focal point F3. In this way, the deformation of an image on the object point away from the optical axis is reduced by using two reflection surfaces.
In the case of applying the X-ray mirror having the aforementioned configuration to a X-ray microscope, light shielding plates are disposed one at each open end of the X-ray mirror so that an X-ray which is reflected on the two reflecting surfaces may be imaged on a detector on the focal point F3. The light shielding plates are adapted to shield that X-rays of an X-ray beam emerging from the object point which are directed toward the detector without being incident on the reflection surfaces. The X-rays enter into the mirror through an annular split defined between the peripheral edge of one of the light shielding plates and one open end edge of the mirror and leave the mirror through an annular slit defined between the peripheral edge of the other light shielding plate and the other open end edge of the mirror. It is necessary that these slits be coaxially located with the center axis of the X-ray mirror with an accuracy of several .mu.m to several 10 .mu.m.
In a conventional X-ray microscope having the X-ray mirror, the two light shielding plates are coupled by a plurality of wires or rods to the mirror so as to be located coaxial therewith. In this structure, however, a part of the slit is shielded by the wires or rods, thus causing a fall in the light collection efficiency of the X-ray beam. Furthermore, due to a fall in the light collection efficiency, a blurred image and a scattering of an X-ray may occur. The scattering of an X-ray induces ghosts. It has also been very difficult, in view of the X-ray not being visible light, to accurately align the light shielding plate with the X-ray mirror and it has also been cumbersome to perform the alignment.